Worst human characteristic EVER!!

I can take stealing, lying, and shady any day, but the worst human characteristic in my opinion is saying you are going to do something and not doing it! Now, I am notorious for having friends that flake, but seriously! I have been told for two months now how I need to visit someone. I finally get a free weekend, talk to them about it, plan it, even discuss it not once, not twice, but three times the day before. I visit and what do I get? A “we can hang out for a little while”. WHAT?!
Worst human characteristic EVER!